The hot bar slots keep getting mixed up after looking into a chest, anvil, etc.

Every time I'm in a world, at somepoint in time, I'll be looking in a chest and all of a sudden like 5 of the hot bar slots are the same item and when I change one of the 5 slots to a different item, ALL OF THEM CHANGE TO THAT ITEM!!!!! It is SOOOO ANOYING!!!! Please fix